The world is changing. As humans, we tend to focus on what happens on land, but the planet’s food systems depend on both terrestrial and marine ecosystems.
Across the globe, ecosystems are undergoing significant change.
"Two groups of plankton form the foundation of the marine food web, and they are so closely linked that a change in one can be profoundly felt by the other. As the ocean warms, both are changing. My research asks how they are changing, in terms of which species are present and how their abundance shifts over time, and what that means for the rest of the food web. If our hypothesis is correct, fish may be getting not only less food, but food of lower quality," says researcher Lauriane Ribas-Deulofeu at Nord University.
A single plankton sample contains thousands of individuals and working through a season’s samples under a microscope takes months. Ribas-Deulofeu uses AI to classify and measure them instead.
The gain is not only speed: it lets scientists monitor more sites more often and can get the results to environmental managers and policymakers in a near real time rather than years later.
"I have thousands of images that need to be analysed and classified. AI can help with this process, but first I had to train the system to recognise the different organisms. That has required numerous hours of work, because distinguishing between the groups is not always easy," she says.
The two main groups of plankton are phytoplankton and zooplankton.
Phytoplankton are microscopic, single-celled organisms, such as green algae or cyanobateria that drift in the water using sunlight to produce their own energy through photosynthesis.
Zooplankton are microscopic animal-like organisms that feed on phytoplankton and other tiny organisms.
Together, they form the foundation of marine and freshwater food webs.
The simplified explanation of the issue is this:
Phytoplankton is essential because they produce most the organic matter that sustains life in the ocean and they do it using little more than sunlight, carbon dioxide and nutrients. They are consumed by zooplankton, which in turn are eaten by fish and other marine animals.
If phytoplankton populations decline or even if their species composition shift, the effects could ripple throughout the food web.
"Phytoplankton are not going to vanish, but which species dominate is changing as is how much biomass they produce. We are also investigating whether bloom timing is shifting and how predators respond. Any of these changes could ripple through the ecosystem, reaching the fish stocks people depend on," Ribas-Deulofeu says.
Plankton also play a crucial role in regulating the Earth's climate. Phytoplankton absorbs carbon dioxide and release oxygen through photosynthesis and some of the carbon they capture sinks to the deep ocean, where it is stored for centuries.
"That is why it is so important to monitor plankton and understand how they are affected by climate change," she says.
Norway is not alone in addressing this challenge. Researchers across Europe are collaborating to better understand changes in marine ecosystems.
"We are building a research network across Europe where we share data, knowledge and equipment. Our EU-funded project BioBoost+ brings together eight institutions across seven countries. In addition, we contribute to a network of around 50 partners across Europe standardizes the use of AI for microplankton image analysis," Ribas-Deulofeu says.